Set along the banks of the Jiuqu River in the 1990s, fisherman Jiang Ye is highly familiar with river currents and skilled at locating old clams. He retrieves a 100-jin old clam that would have paid off the fishing fleet's debts, only for his catch to be falsely claimed by his older brother Jake Hale. Jake colludes with jeweler Derek Zane to monopolize clam purchasing channels, suppress prices and persecute fishermen living along the river. Refusing to submit, Jiang Ye braves dangerous rapids to find a rare, unusual clam that yields a four-colored Iridescent Pearl. He enters the capital-controlled Clam King championship competition, using his expert clam identification skills to fight for livelihood and dignity for the local working-class fishermen.
